Like water flowing downhill, and equally benevolent

There is still doubt, but there seems to be a good chance that the Flores Hobbit was a member of a distinct hominid species, rather than some homo sap with a nasty case of microcephalic dwarfism. If this is the case, the Hobbits are likely descended from a small, Australopithecus-like population that managed to move from Africa to Indonesia without leaving any fossils in between, or from some ancient hominid (perhaps homo erectus) that managed to strand themselves on Flores and then shrank, as many large animals do when isolated on islands. Island dwarfing of a homo erectus population is the dominant idea right now.

However, many proponents are really bothered by how small the Hobbit’s brain was. At 400 cc, it was downright teeny, about the size of a chimpanzee’s brain. Most researchers seem to think that hominid brains naturally increase in size with time. They also suspect that anyone with a brain this small couldn’t be called sentient – and the idea of natural selection driving a population from sentience to nonsentience bothers them.

“An infectious cancer! Can you believe it?”

Elephants replace their teeth four to six times in their lifetime. At about 40 to 60 years of age, the elephant no longer has teeth and will likely die of starvation.

“I used to be a dog!”

The primary function of the adult is reproduction; the mouthparts are vestigial, and the digestive system is filled with air.

“It’s like what he did to Henrietta Lacks! She used to be a human—“

There is a mechanism that might explain what happened on Flores – partial mutational meltdown. Flores is not that big an island and the population density of homo-erectus type hunter-gatherers must have been low – certainly lower than that of contemporary hunter-gatherers, who have much more sophisticated tools. Thus the hobbit population was likely small. It may not have been possible to sustain a high-performing brain over the long haul in that situation.

“—and now she’s this… this thing… that reproduces in medical laboratories!”

Intelligence is negatively related to number of children, which reduces the average US IQ .8 points per generation. But Woodley et al found decreasing IQ trend of 1.2 IQ points per decade: a much steeper decline.

“And then there are those monkeys!”

Given that their brains performed poorly – while the metabolic costs were as high as ever – selection would have shrunk their brains. Over hundreds of thousands of years, this could well have generated the chimp-sized brain we see in the LB1 skeleton.

“You know the ones—“

The white supremacy underlying demographic winter prophecies

“—the ones that used to be—”

In principle, if the population is the right size and one adaptive function is considerably more complicated than others, presenting a bigger mutational target, you might see a population suffer a drastic decline in that function while continuing to exist. There is reason to think that intelligence is the most complex adaptation in hominids. More than half of all genes are expressed in the brain, and it seems that a given degree of inbreeding depression – say cousin marriage – depresses IQ more than other traits.

Of course, this could only have happened if there was an available ecological niche that did not require human-level intelligence. And there was such an opening: Flores had no monkeys.

and þe blind idiot, þe noxious Azathoth shal arise from þe middle of þe World where all is Chaos & Destruction